The present invention relates to a plug-type lock, that is insertable in the aligned openings of two members to obstruct relative movement between the members. An example of an environment for such a lock is a casing and base forming the housing of a warning light as shown in U.S. Pat. No. 3,697,738, issued to Decker et al., on Oct. 10, 1972 for "Warning Light Housing."
Street construction barricades are commonly provided with electric warning lights to enhance vehicular safety. Since such warning lights are vulnerable to theft by delinquent persons, it is desirable to permanently mount them on the barricade to prevent larcenous removal. For example, in U.S. Pat. No. 3,015,804 the entire housing for a warning light is permanently attached to the barricade. On the other hand, permanent mounting structures generate serviceability problems. Warning lights require periodic upkeep, such as routine battery changes and bulb replacement, and parts repair necessitated by adverse weather conditions and rough handling by construction personnel. As a result, it is desirable to have a warning light housing that is easily removable from the barricade by authorized maintenance workers. In the aforementioned U.S. Pat. No. 3,697,738, to which reference may be had for further description, these conflicting difficulties are resolved by providing a housing including a base secured to the barricade and a casing affixed to the base. The constituents of the light system--batteries, switches, flasher circuit, lamp, wiring, etc.--are enclosed between the base and casing. A through bolt passes through a bore in the base and extends into an aperture in the barricade. A mounting nut and its surrounding nut cup are placed on the end of the bolt protruding into the barricade. A special tool is required to restrain rotation of the mounting nut as the bolt is turned into the nut fastening the base to the barricade. This type of mounting provides a semi-permanent attachment, in that separation of the housing from the barricade can be accomplished generally only through utilization of the special tool.
The noted arrangement is quite satisfactory, but it does present a problem in that, the connection between the base and casing is still somewhat susceptible to thievish tampering. A locking screw extends through an aperture in the casing into an internally threaded bore in the base. A recess encircles the aperture to present a substantially sunken enclosure for the locking screw in its fully tightened position. Despite this fastening deterrent, stealthy individuals have been able to achieve access to and purloin the components of the light system within the housing.
The present invention contemplates an improved locking device for holding the structural constituents of a warning light housing in secured relationship, and it is also intended for any other uses in which two members are to be locked together by insertion of a plug-type lock into the two members.